Further studies to investigate the pathogenesis of fever are planned in the following areas: 1. The pathology of inflammatory response in lizards infected with Aeromonas in relation to fever. 2. Purification of rabbit endogeneous pyrogen (EP) and the role of prostaglandins. 3. Dynamics of pyrogen formation and release in human and rabbit mononuclear phagocytes in various stages of differentiation. 4. EP production in cells in biopsy samples from patients with febrile and non-febrile disease. 5. Production and properties of antibody to human EP. 6. Mechanism of tolerance to fever in rabbits and guinea pigs desensitized to protein antigens. 7. Role of Kupffer cells in immune fever in rabbits. 8. Pyrogenic factors in purified flu virus (with Edwin Kilborne).